Advances in Dielectric Materials and Electronic Devices: Piezoelectrics, Microwave Materials, and Conductive Applications
Sponsored by: ACerS Electronics Division
Program Organizers: Amar Bhalla, University of Texas; Ruyan Guo, University of Texas at San Antonio; Rick Ubic, Boise State University; Matjaž Spreitzer, Jožef Stefan Institute

Monday 2:00 PM
October 10, 2022
Room: 410
Location: David L. Lawrence Convention Center

Session Chair: Ruyan Guo, University of Texas San Antonio


2:00 PM  
Carbon-based Glass Foam Composites for High Power Microwave Absorption: Ratiba Benzerga1; Vincent Laur2; Laurent Le Gendre1; Ronan Lebullenger3; Ala Sharaiha1; 1University of Rennes, IETR; 2Lab-STICC ; 3Univ Rennes, ISCR
    Recycling chains of glass wastes were largely developed but some types of glass, polluted with heavy metals, pose a tougher problem. Indeed, glass wastes from the electronics should be treated in a specific recycling process. This is the case of Cathode Ray-Tubes (CRT) found in older-style TV screens and monitors. Glass-foam manufacture is a promising mode for re-using CRT glasses; this cellular material combines low density, low thermal conductivity, excellent thermal stability, and high rigidity. For this work, we focused our attention on the microwave absorption property. Inorganic additives can be used to reinforce this property. Indeed, when Carbon is used as the foaming agent, high dielectric losses are observed. In this work, we studied the impact of the glass cullet and the foaming agent rate on the density and the microwave behavior of glass-foams. The thermal stability and the high-power microwave absorbing application of these foams will be presented.

2:20 PM  
TTB Strontium Tantalum Ceramics for Integration into Miniature Dielectric Resonator Antennas: Matthew Julian1; Mouad Barzani1; Mohamad Haydoura1; Ratiba Benzerga1; Laurent Le Gendre1; Ala Sharaiha1; Francois Chevire2; Claire Le Paven1; 1Université de Rennes, CNRS, IETR-UMR 6164, F-35000 Rennes, France; 2Université de Rennes, CNRS, ISCR-UMR 6226, F-35000 Rennes, France
    This study will investigate the viability of utilizing tetragonal tungsten bronze (TTB) phase β’-SrTa2O6 ceramics for integration into miniaturized dielectric resonator antennas applicable for use in 5G devices. In low frequencies, dielectric measurements are conducted via a metal-insulator-metal structure, showing stable permittivity and losses (ε = 100, tanδ = 1x10-4 at 10 kHz). High frequency dielectric characterization is performed around 3.5 GHz using a resonant cavity, showing a permittivity of 69, dielectric losses tanδ of 4x10-3, and a temperature coefficient of 195 ppm/℃. Optimization of sintering conditions to obtain high relative density ceramics, while monitoring the microstructure for abnormal grain growth or texturing and maintaining phase purity, further reduce the dielectric losses. These results, demonstrating that TTB β’-SrTa2O6 ceramics provide the dielectric properties suitable for miniaturized DRA antennas, will be supplemented by the performances of the DRA’s after their realization and characterization in a near-field measurement base.

2:40 PM  
New Insights into Bismuth Sodium Titanate Ferroelectric Ceramics: Zhongming Fan1; Clive Randall1; 1Penn State University
    Bismuth sodium titanate (BNT) is one of the most popular lead-free piezoelectric ceramics. The functional potentials of BNT-based materials are widely appreciated, yet the defect chemistry and polarization dynamics are far from being fully elaborated. Oxygen vacancies and bismuth/sodium vacancies are the predominant point defects. The oxygen vacancy could lead to considerable ionic conduction, thereby the significant resistance degradation under DC bias. The bismuth vacancies, on the other hand, play crucial role in the phase transition behaviors. In the presentation, the defect chemistry and its impact on the polarization dynamics will be systematically discussed.

3:00 PM  
Enhanced Piezocomposite Transducers with 3D Printed Piezoelectric PZT: Shawn Allan1; Justin Tufariello2; Barry Robinson3; Nicholas Voellm1; Nicole Ross1; Ryan Fordham1; Casey Corrado2; Alex Angilella2; Leslie Riesenhuber2; Brian Pazol3; 1Lithoz America LLC; 2MITRE Corporation; 3MSI Transducers Corp.
    Ceramic additive manufacturing (AM) offers the potential to create piezocomposite transducers with refined and customizable features that result in enhanced sensing performance for underwater acoustics. Novel geometries that are otherwise impossible to fabricate with conventional manufacturing methods may be efficiently created through AM processes to increase transducer sensitivity and improve directionality. The lithography-based ceramic manufacturing (LCM) process has been used to create innovative structures in PZT-5H. Broad material knowledge was used to create ceramic powders for slurry creation and to refine post-processing procedures for repeatable sintered material properties (density, dielectric constant, and piezoelectric coefficient) equivalent to conventionally produced bulk ceramic. Piezocomposite transducers produced with printed PZT were compared against conventionally manufactured replica transducers with excellent performance matching. Coupled-acoustic finite element analysis (FEA) was used to design and evaluate distributed composite apertures and auxetic structures with improved performance, which are only feasible to manufacture with AM.

3:20 PM Break

3:40 PM  
Dielectric Behavior of Electronic Materials, Specifically Silicon, Solder and Conductive Thick Films: Deborah Chung1; 1State University of New York Buffalo
    The dielectric behavior refers to electric polarization behavior. This behavior has long been studied in relation to nonconductive materials. However, it occurs in conductive materials too. Although the polarization in a conductor is low, the polarizability (which is described by the permittivity) is high. For conductor applications, the dielectric behavior is disadvantageous, as it impedes conduction and delays the signal propagation. This work reports the permittivity of silicon wafer, solder (Sn-4Ag) and conductive thick films (e.g., silver-particle thick film). The polarization stems from the interaction of a small fraction of the carriers with the atoms. This interaction occurs mainly at defects. Due to the abundance of interfaces in the solder alloy (phase boundaries) and conductive thick films (inter-particle interfaces), the relative permittivity is as high as 1,000,000 (kHz range). For single-crystal boron-doped silicon wafer, the in-plane relative permittivity is lower, but still high (1,000), due to the dopant (substitutional impurity).

4:00 PM  
Effects of β-Silicon Carbide Microstructure on the Electrical Response of PMMA Matrix Nanocomposites: Roshaun Titus1; Rosario Gerhardt1; 1Georgia Institute of Technology
    Investigated are influences of the ceramic-filler polymer interfaces on the conductivity of β-SiC PMMA nanocomposites. Three SiC fillers were used: micron-sized, nano-sized, and whisker. The composites were fabricated via mechanical mixing and compression molding. Impedance spectroscopy was used to characterize the electrical response of the composites under AC voltage. Nano-SiC resulted in composites with the lowest percolation threshold, at 3 PHR. The whisker-SiC experienced percolation after 12 PHR. However, the largest conductivity measured came from the whisker-SiC at 15 PHR, surpassing that of the nano-SiC maximum measured conductivity. In-situ impedance measurements of compressed SiC fillers revealed that micron-SiC was the most conductive of the three fillers. However, micron-SiC composites gave the lowest conductivity of all composites fabricated. Micron-SiC composites exhibited a drop in conductivity with increasing filler content, suggesting different surface interactions than the others. Detailed microstructure investigations are ongoing.

4:20 PM  
Sensitivity Analysis of PZT-4 Material Properties Using the Complex Variable Finite Element Method: Carlos Acosta1; Amar Bhalla1; Ruyan Guo1; 1University of Texas at San Antonio
    The sensitivity analysis of electromechanical properties for PZT-4 has been performed using the complex variable finite element method (ZFEM) on a two-dimensional geometry. A thin plate model is subjected to a uniform boundary load to induce mechanical strain yielding variations in the electric potential field. The numerical results from mechanical displacements and electric potential fields are verified against the solution from a commercial software. The first order derivatives obtained from ZFEM illustrate the sensitivity of material properties as design parameters for real time tunability of manufacturing processes in additive manufacturing. Results show that the largest sensitivities emerge from elastic constants and followed by the dielectric and piezoelectric constants in the poling direction affecting the mechanical deformation and electric potential field.